lodash.uniqby

What is lodash.uniqby?

The lodash.uniqby package is a part of the Lodash library, specifically designed for creating arrays with unique elements based on a specified criterion. It allows for filtering out duplicate values in an array by comparing the result of running each element through an iteratee function. This is particularly useful for dealing with arrays of objects where uniqueness should be determined based on specific properties.

What are lodash.uniqby's main functionalities?

Removing duplicate objects based on a specific property

This feature allows for the removal of duplicate objects from an array based on a specific property. In this example, the array of objects is filtered to ensure uniqueness based on the 'id' property.

[{ 'id': 1, 'name': 'John' }, { 'id': 2, 'name': 'Doe' }, { 'id': 1, 'name': 'John' }].filter((v, i, a) => a.findIndex(t => (t.id === v.id)) === i)

Other packages similar to lodash.uniqby

underscore

Underscore is a utility library with similar functionalities to lodash, including methods for working with arrays, objects, and functions. It offers a 'uniq' method that can be used similarly to 'uniqBy' for arrays of primitive types but lacks the direct equivalent of specifying an iteratee for complex uniqueness conditions.

ramda

Ramda is a functional programming library that includes a 'uniqBy' function, which works similarly to lodash.uniqby. It emphasizes a more functional programming approach, which might be preferred by developers looking for composability and immutability. Ramda's 'uniqBy' also removes duplicates based on the provided iteratee function.

README

lodash.uniqby v4.2.0

The lodash method _.uniqBy exported as a Node.js module.

Installation

Using npm:

$ {sudo -H} npm i -g npm
$ npm i --save lodash.uniqby

In Node.js:

var uniqBy = require('lodash.uniqby');

See the documentation or package source for more details.